Each year an estimated 8,000 to 10,000 apparently healthy infants die while resting in their cribs, thus giving rise to the terms "crib death" and Sudden Infant Death Syndrome. Unfortunately, the specific cause of these deaths remains unknown, with a resulting lack of any means of prevention.
Recently, however, it has been discovered that suffocation and SIDS are indistinguishable on postmortem examination. Infant suffocation can occur when exhaled carbon dioxide accumulates around the infant's face, as by becoming trapped by the mattress and bedding, since infants are generally placed on their stomachs to prevent the aspiration of regurgitated fluids during sleep. The trapped carbon dioxide prevents the intake of proper amounts of oxygen and the infant loses consciousness and death occurs soon thereafter.